Illuminating device, display device, and television receiving device

ABSTRACT

Provided is an illuminating device capable of preventing a light guide plate from being shaved because of contact with a fixation member on a back face side of an end portion of the plate. The illuminating device includes alight guide plate ( 11 ), a chassis ( 14 ) housing the plate and including a bottom plate ( 14   a ), and a light source holding member ( 15 ) fixed to the bottom plate by a fixation screw ( 16 ) and holding a light source ( 21 ) close to a light entrance face ( 11   a ) of the light guide plate, and further includes a concave portion  12  preventing contact between a screw head ( 16   a ) of the screw and the light guide plate and disposed on a back face of an end portion ( 11   d ) of the light guide plate at a position where the head is to be disposed if the screw is disposed on a side of the back face.

TECHNICAL FIELD

The present invention relates to an illuminating device, and a displaydevice, and a television receiving device.

BACKGROUND ART

A liquid crystal display panel with a transmissive liquid crystaldisplay device includes the liquid crystal display device, and anilluminating device that is disposed behind the liquid crystal displaypanel so as to project light thereonto. A side (edge) light typeilluminating device is known as this type of illuminating device, whichincludes a light guide plate that defines a clear plate made from anacrylate resin, and a light source that is disposed along one side or aplurality of sides of the light guide plate. The side light typeilluminating device having this configuration has the advantage of beingeasily reduced in thickness compared with a direct illuminating devicehaving a configuration that a light source is disposed behind a liquidcrystal display panel.

Especially when the side light type illuminating device includes an LED(Light-Emitting Diode) as the light source, the light source has theadvantages of a long life and a high luminous efficiency, which has beenreceiving widespread attention. FIGS. 16 and 17 are an explodedperspective view and a cross-sectional view of relevant components,respectively, which show a schematic configuration of a liquid crystaldisplay device including a side light type illuminating device thatincludes LEDs as described above.

As shown in FIGS. 16 and 17, a liquid crystal display device 100includes a liquid crystal display panel 103, an illuminating device(backlight device) 104, and other components.

A bezel 102 has a frame shape so as to cover a peripheral portion of theliquid crystal display panel 103. The bezel 102 is, together with achassis 114, arranged to ensure strength of the entire liquid crystaldisplay device 100. The liquid crystal display panel 103 consists of twoglass substrates that are bonded together while sandwiching liquidcrystals therebetween. The liquid crystal display panel 103 is arrangedto display an image on its front face by using light emitted from theilluminating device 104.

The illuminating device 104 includes the chassis 114 having the shape ofa box of low height. Optical sheets 107 to 109, a light guide plate 111,a reflection sheet 110, and an LED board 120 are housed inside of theilluminating device 104.

The light guide plate 111 includes a light entrance face 111 a fromwhich light emitted from LEDs 121 mounted on the LED board 120 enters,and a light exit face 111 b from which the light that has entered fromthe light entrance face 111 a is emitted upward (in a direction of lightprojection) as shown in FIG. 17. The light entrance face 111 a defines alateral end face of an end portion 111 d of the light guide plate 111.The light exit face 111 b defines a front face of the light guide plate111.

The reflection sheet 110 is disposed so as to cover a back face 111 c ofthe light guide plate 111, which is an opposite face to the light exitface 111 b of the light guide plate 111. The optical sheets 107 to 109include a diffusion sheet and a lens sheet, and are disposed so as tocover the light exit face 111 b of the light guide plate 111.

A stack of the optical sheets 107 to 109, the light guide plate 111, andthe reflection sheet 110 is disposed on a bottom plate 114 a of thechassis 114 while fixed thereon by a frame 105 having a frame shape.

The plurality of LEDs 121 mounted on the LED board 120 are disposedclose to the light entrance face 111 a of the light guide plate 111. Theplurality of LEDs 121 are spaced apart from each other at specifiedintervals along the light entrance face 111 a such that light emittingsurfaces 121 a of the LEDs 121 oppose the light entrance face 111 a ofthe light guide plate 111. In this case, the LED board 120 is attachedto a light source holding member 115 disposed on the bottom plate 114 aclose to a side plate 114 b of the chassis 114.

The light source holding member 115 has the shape of a so-called bracket(L-shaped mounting hardware), and is made by cutting aluminum. In thiscase, the light source holding member 115 consists of a long plate 115 ato which the LED board 120 is attached, and a long plate 115 b arrangedto be fixed to the bottom plate 114 a of the chassis 114 by fixationscrews 116 that define fixation members such as flat head screws andhexagonal screws, the plate 115 a and the plate 115 b being disposed soas to have an L-shape. The following literature is cited as a prior artliterature relating to the present invention.

CITATION LIST Patent Literature

-   PTL 1: JP 2008-41641

SUMMARY OF INVENTION Technical Problem

In recent years, a frame region of the liquid crystal display device 100having the configuration described above has been desired to be madenarrow. Making the frame region narrow defines reducing the area of aframe region A that surrounds a display portion of the liquid crystaldisplay panel 103 as shown in FIG. 17.

As shown in FIG. 18A, the area of the frame region A can be reduced bydisposing the plate 115 b of the light source holding member 115 on theside of the light guide plate 111, not on the side of the side plate 114b of the chassis 114, to decrease the distance between the plate 115 aof the light source holding member 115 and the side plate 114 b of thechassis 114 compared with the configuration shown in FIG. 17.

However, a problem arises that if screw heads 116 a of the fixationscrews 116 that jut upward out of a front face of an end portion of theplate 115 b are disposed on a back face side of the end portion 111 d ofthe light guide plate 111 in the configuration that the plate 115 b ofthe light source holding member 115 is disposed on the side of the lightguide plate 111 as shown in FIG. 18A, some portions of the light guideplate 111, which make contact with the screw heads 116 a when the lightguide plate 111 is shaken by vibrations made during transportation ofthe liquid crystal display device 100, are shaved to produce shavings118.

The shavings 118 produced as described above adhere to the lightemitting surfaces 121 a of the LEDs 121, or enter into a front face sideof the optical sheets 107 to 109, so that luminance unevenness coulddevelop in images displayed on the liquid crystal display panel 103 toreduce the display quality.

An object of the present invention is to provide an illuminating device,a display device, and a television receiving device, which are capableof preventing contact between a jutting portion of a fixation member andaback face of an end portion of a light guide plate and thus preventingthe light guide plate from being shaved when the illuminating device,the display device, and the television receiving device have aconfiguration that a light source holding member, which is arranged tohold a group of aligned light sources that are opposed to a lateral endface of the light guide plate disposed on an inner bottom face of achassis from which light enters and arranged to project light onto alight entrance face of the light guide plate, is fixed to a bottom plateof the chassis by the fixation member.

Solution to Problem

To achieve the objects and in accordance with the purpose of the presentinvention, an illuminating device of the present invention includes alight guide plate including a light exit face having a planar shape,alight entrance face on an end portion of light exit face, from whichlight projected from a light source enters, and a back face opposite tothe light exit face, a chassis arranged to house the light guide plateand including a bottom plate on which the light guide plate is disposed,and a light source holding member fixed to the bottom plate of thechassis by a fixation member and arranged to hold the light source so asto be disposed close to the light entrance face of the light guide platehoused in the chassis, and further includes a concave portion arrangedto prevent contact between the fixation member and the light guideplate, the concave portion being provided on the back face of the endportion of the light guide plate at a position where the fixation memberis to be disposed if the fixation member by which the light sourceholding member is fixed to the bottom plate of the chassis is disposedon a side of the back face of the end portion of the light guide plate.

This configuration of including the concave portion disposed on the backface of the end portion of the light guide plate can prevent contactbetween the light guide plate and the fixation member on the back faceside of the light guide plate, which can accordingly prevent shavingsfrom being produced from the light guide plate when the light guideplate is shaken. Thus, no shavings are produced to be adhered to thelight source, which can prevent luminance unevenness resulting from suchshavings.

In this case, it is preferable that the light source holding memberfurther includes a plate to which the light source is attached and aplate arranged to be fixed to the bottom plate of the chassis by thefixation member, the plates being disposed having an L-shape, wherein anend portion of the plate arranged to be fixed to the bottom plate, theend portion being disposed on a side of the light guide plate, overlapswith the back face of the end portion of the light guide plate when seenin a plan view. In this configuration, because the plate arranged to befixed to the bottom plate is disposed on the side of the light guideplate, which is opposite to the side of the side plate of the chassis,the distance between the plate to which the light source is attached andthe side plate of the chassis can be decreased, which can make a frameregion narrow. In addition, because the concave portion disposed on theback face of the end portion of the light guide plate can preventcontact between the fixation member, by which the plate arranged to befixed to the bottom plate is fixed to the bottom plate of the chassis,and the back face of the end portion of the light guide plate, shavingsare prevented from being produced from the light guide plate when thelight guide plate is shaken. It is also preferable that light sourceholding member includes the plate to which the light source is attached,and the plate arranged to be fixed to the bottom plate, the plates beingdisposed having an inverted T-shape, a laterally laid U-shape, or aninverted Y-shape.

It is also preferable that the concave portion has a notch shapeextending from the light entrance face of the light guide plate. Thisconfiguration allows the concave portion to be produced more easily bymaking cutting at a given portion in the back face of the end portion ofthe light guide plate. Thus, the cost of processing and production ofthe concave portion can be reduced.

It is also preferable that a plurality of fixation members are disposedin a longitudinal direction of the light entrance face of the lightguide plate, and the concave portion has a strip shape when seen in aplan view to house the plurality of fixation members in a lump. Thisconfiguration allows the concave portion to be produced in order toprevent contact with the plurality of fixation members by makingone-time cutting in the back face of the end portion of the light guideplate. Thus, the cost of processing and production of the concaveportion can be reduced.

It is also preferable that the concave portion has a round shape, anoval shape, a triangular shape, a quadrangular shape, or a hexagonalshape. It is also preferable that the fixation member defines a flathead screw, a hexagonal screw, a rivet, or a clip arranged to sandwichthe light source holding member and the bottom plate of the chassis,which are widely used fixing members.

In another aspect of the present invention, a display device of thepresent invention includes the illuminating device described above, anda display panel arranged to make a display by using the light emittedfrom the illuminating device. Including the illuminating device havingthe configuration that luminance unevenness does not easily result fromshavings produced from the light guide plate, the display device of thepresent invention can achieve an image display where reduction in imagequality is prevented.

The examples of the display panel include a liquid crystal di splaypanel. The examples of the di splay device include a liquid crystaldisplay device, and the liquid crystal display device can be applied tovarious uses, such as a display for a television receiving device and adisplay for a personal computer. In particular, the liquid crystaldisplay device can be preferably applied to a large-screen display.

Advantageous Effects of Invention

According to the present invention, the configuration of including theconcave portion disposed on the back face of the light guide plate canprevent contact between the light guide plate and the fixation member onthe back face side of the light guide plate, which can accordingly prevent shavings from being produced from the light guide plate when thelight guide plate is shaken. Thus, no shavings are produced to beadhered to the light source, which can prevent luminance unevennessresulting from such shavings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an exploded perspective view showing a schematic configurationof a television receiving device of a preferred embodiment of thepresent invention.

FIG. 2 is an exploded perspective view showing a schematic configurationof a liquid crystal display device included in the television receivingdevice shown in FIG. 1.

FIG. 3 is an enlarged cross-sectional view showing assembled relevantcomponents of the liquid crystal display device shown in FIG. 2.

FIG. 4A is a plan view showing concave portions of the light guide plateof a first embodiment of the present invention, which are seen frombehind. FIG. 4B is an external perspective view showing the same.

FIG. 5A is a plan view showing a concave portion of the light guideplate of a second embodiment of the present invention, which is seenfrom behind. FIG. 5B is an external perspective view showing the same.

FIGS. 6A and 6B are views of modification 1 and modification 2 of theconcave portions of the light guide plate of the first embodiment. FIG.6A is an external perspective view showing the concave portions of thelight guide plate of modification 1. FIG. 6B is an external perspectiveview showing the concave portions of the light guide plate ofmodification 2.

FIGS. 7A and 7B are views of modification 3 and modification 4 of theconcave portions of the light guide plate of the first embodiment. FIG.7A is an external perspective view showing the concave portions of thelight guide plate of modification 3. FIG. 7B is an external perspectiveview showing the concave portions of the light guide plate ofmodification 4.

FIG. 8 is a cross-sectional view showing a liquid crystal display deviceincluding the light guide plate having a different configuration fromthe light guide plate shown in FIG. 3.

FIG. 9A is a plan view showing a light guide plate of a third embodimentof the present invention, which is seen from behind. FIG. 9B is anexternal perspective view showing the same.

FIG. 10A is a plan view showing a light guide plate of a fourthembodiment of the present invention, which is seen from behind. FIG. 10Bis an external perspective view showing the same.

FIGS. 11A and 11B are views of modification 1 and modification 2 ofconcave portions of the light guide plate of the third embodiment. FIG.11A is an external perspective view showing the concave portions of thelight guide plate of modification 1. FIG. 11B is an external perspectiveview showing the concave portions of the light guide plate ofmodification 2.

FIGS. 12A and 12B are views of modification 3 and modification 4 of theconcave portions of the light guide plate of the third embodiment. FIG.12A is an external perspective view showing the concave portions of thelight guide plate of modification 3. FIG. 12B is an external perspectiveview showing the concave portions of the light guide plate ofmodification 4.

FIGS. 13A and 13B are views of modification 1 and modification 2 of alight source holding member of a preferred embodiment of the presentinvention. FIG. 13A is a cross-sectional view showing the light sourceholding member of modification 1. FIG. 13B is a cross-sectional viewshowing the light source holding member of modification 3.

FIG. 14 is a cross-sectional view showing the light source holdingmember of modification 3 of the preferred embodiment.

FIGS. 15A and 15B are views of modification 1 and modification 2 of afixation member of a preferred embodiment of the present invention. FIG.15A is a cross-sectional view showing the fixation member ofmodification 1. FIG. 15B is a cross-sectional view showing the fixationmember of modification 2.

FIG. 16 is an exploded perspective view showing a schematicconfiguration of a conventional liquid crystal display device.

FIG. 17 is an enlarged cross-sectional view of assembled relevantcomponents of the conventional liquid crystal display device shown inFIG. 16.

FIG. 18A is a cross-sectional view showing a liquid crystal displaydevice including a light source holding member having a differentconfiguration from the light source holding member shown in FIG. 16.FIG. 18B is an explanatory view showing a problem in the liquid crystaldisplay device shown in FIG. 18A.

DESCRIPTION OF EMBODIMENTS

Detailed descriptions of preferred embodiments of an illuminatingdevice, a display device, and a television receiving device of thepresent invention will now be provided with reference to theaccompanying drawings.

FIG. 1 is an exploded perspective view showing a schematic configurationof a television receiving device of the present embodiment. A televisionreceiving device 50 includes a liquid crystal display device 1, a tuner51, speakers 52, and an electric power supply 53 arranged to supplyelectric power to the liquid crystal display device 1, the tuner 51, andthe speakers 52. The liquid crystal display device 1, the tuner 51, thespeakers 52 and the electric power supply 53 are housed in a housingconsisting of a front side cabinet 54 and a back side cabinet 55, andsupported by a stand 56. The liquid crystal display device 1 is housedin an upright position such that a display surface la of the liquidcrystal display device 1 is oriented vertically.

The liquid crystal display device 1 includes a liquid crystal displaypanel 3, and an illuminating device (backlight device) 4 arranged toproject light thereonto, which are held together by a bezel 2 having aframe shape as shown in FIG. 2. The bezel 2 has a frame shape to cover aperipheral portion of the liquid crystal display panel 3. The bezel 2is, together with a chassis 14 of the illuminating device 4, arranged toensure strength of the entire liquid crystal display device 1.

The liquid crystal display panel 3 has a rectangular shape when seen ina plan view, and includes a pair of glass substrates consisting of athin film transistor (TFT) array substrate and a color filter (CF)substrate, which are bonded together so as to be opposed parallel toeach other having a given space therebetween, in which liquid crystalsare filled.

A plurality of TFTs and pixel electrodes are arranged in a matrix on theTFT array substrate. A plurality of color patterns are arranged in amatrix on the CF substrate, and a common electrode is provided over theentire surface of the CF substrate. By varying a voltage applied to thepixel electrodes and the common electrode, alignment of the liquidcrystals can be controlled, whereby an image can be displayed. Theliquid crystal display panel 3 includes polarizing plates on a front anda back face.

The illuminating device 4 defines a so-called side (edge) light typeilluminating device. The illuminating device 4 includes the box-shapedchassis 14 that has an opening that is open to the side of the liquidcrystal display panel 3, and optical sheets 7 to 9 disposed covering theopening of the chassis 14 as shown in FIG. 2. In addition, the chassis14 includes an LED board 20 on which a plurality of LEDs (Light EmittingDiodes) 21 are mounted, a light guide plate 11 arranged to guide lightemitted from the LEDs 21 to the side of the liquid crystal display panel3, and a reflection sheet 10 disposed behind the light guide plate 11,which are housed inside of the chassis 14.

The frame 5 is arranged to fix the optical sheets 7 to 9, the lightguide plate 11 and the reflection sheet 10, which are stacked in thisorder from the top, to the chassis 14. In this case, the frame 5 has aframe shape lying on an outer peripheral portion of the light guideplate 11, and is capable of pressing the almost entire outer peripheralportions of the optical sheets 7 to 9 and the light guide plate 11 fromthe front side. The frame 5 is made preferably from a black syntheticresin, and has a light shielding effect. The frame 5 has a configurationof receiving the back face of the outer peripheral portion of the lightguide plate 11 by its frame-shaped front face.

The chassis 14 has the shape of a box of low height and is preparedpreferably by bending a metal plate made from aluminum. The chassis 14is arranged to house the optical sheets 7 to 9, the light guide plate11, the reflection sheet 10, a light source holding member 15, and theLED board 20. The chassis 14 includes a bottom plate 14 a having arectangular shape when seen in a plan view, and side plates 14 b thaterect from the four sides of the outer edge of the bottom plate 14 a.The side plates 14 b have a configuration that the frame 5 and the bezel2 can be attached thereto by screws.

The three optical sheets 7 to 9 define thin resin sheets, which have arectangular shape when seen in a plan view. The three optical sheets 7to 9 are disposed on the front side of the light guide plate 11 (theside from which light is emitted) and lie between the liquid crystaldisplay panel 3 and the light guide plate 11. The optical sheets 7 to 9preferably define the polarization selective reflection sheet 7, thelens sheet 8 and the diffusion sheet 9, which have a thickness of about0.1 to 0.5 mm, and are stacked in this order from the top.

In this embodiment, the diffusion sheet 9 is arranged to diffuse thelight emitted from the light guide plate 11, allowing uniformalizationof luminance distribution of the light. The lens sheet 8 is arranged togather the light that is emitted from the diffusion sheet 9 to allowenhancement of the front luminance of the light. The polarizationselective reflection sheet 7 is arranged to selectively reflect thelight emitted from the lens sheet 8 so that the light is not absorbed bya polarizing plate (not illustrated) that is attached on the back sideof the liquid crystal display panel 3.

The light guide plate 11 has a rectangular shape when seen in a planview, and preferably defines a clear plate made from a resin and havinga thickness of about 3 to 4 mm. The light guide plate 11 includes alight entrance face 11 a from which light emitted from the LEDs 21enters, and a light exit face lib from which the light that has enteredfrom the light entrance face 11 a is emitted upward (in a direction oflight projection). The light entrance face 111 a defines a lateral endface of a given end portion 11 d of the light guide plate 11. The lightexit face lib defines a front face of the light guide plate 11.

The light guide plate 11 is arranged to repeatedly reflect the light,which has entered from the light entrance face 11 a, between the lightexit face (front face) lib and a back face 11 c, which is the oppositeface to the light exit face lib, to planarly diffuse the light insidethe light guide plate 11. The light guide plate 11 includes a pluralityof scattering members (not illustrated) on the back face 11 c, which arearranged to scatter the light, which has entered from the light entranceface 11 a, and emit the light from light exit face 11 b. The scatteringmembers are preferably provided thereon by dotting paint containing awhite pigment in a printing method on the back face 11 c of the lightguide plate 11.

The plurality of LEDs 21 mounted on the LED board 20 are disposed closeto the light entrance face 11 a of the light guide plate 11. Theplurality of LEDs 11 are spaced apart from each other at specifiedintervals along the light entrance face 11 a such that light emittingsurfaces 21 a of the LEDs 21 oppose the light entrance face 11 a of thelight guide plate 11. In this case, the LED board 20 is attached to thelight source holding member 15 having an L-shape so as to stand thereon,while the light source holding member 15 is fixed to the bottom plate 14a close to the side plate 14 b of the chassis 14.

The light source holding member 15 has the shape of a so-called bracket(L-shaped mounting hardware), and is made by cutting aluminum. In thiscase, the light source holding member 15 consists of a long plate 15 ato which the LED board 20 is attached, and a long plate 15 b arranged tobe fixed to the bottom plate 114 a of the chassis 114, the plate 115 aand the plate 115 b being disposed so as to have the L-shape.

The plate 15 b of the light source holding member 15 includes holes 15 cdisposed at three positions of both the ends and the middle of the plate15 b, the holes 15 c having a configuration that fixation screws 16 thatdefine fixation members such as flat head screws and hexagonal screwspass through the holes 15 c. In addition, the bottom plate 14 a of thechassis 14 includes screw holes 14 c disposed at positions correspondingto the three positions for the holes 15 c, the screw holes 14 c having aconfiguration that end portions of the fixation screws 16 are screwedinto the screw holes 14 c. Thus, the light source holding member 15 hasthe configuration that the fixation screws 16 are made to pass throughthe holes 15 c of the plate 15 b to be screwed into the screw holes 14 cof the bottom plate 14 a, whereby the light source holding member 15 canbe fixed to a given position close to the side plate 14 b of the chassis14.

In the present embodiment, the area of a frame region A can be reducedby disposing the plate 15 b of the light source holding member 15 on theside of the light guide plate 11, not on the side of the side plate 14 bof the chassis 14, to decrease the distance between the plate 15 a ofthe light source holding member 15 and the side plate 14 b of thechassis 14 as shown in FIG. 3.

The reflection sheet 10 is disposed so as to cover the back face 11 c ofthe light guide plate 11, which is an opposite face to the light exitface 11 b of the light guide plate 11. In the present embodiment, thereflection sheet 10 is disposed on the bottom plate 14 a of the chassis14. The reflection sheet 10 is arranged to reflect the light toward thelight guide plate 11, the light emitting toward the back side from theback face 11 c of the light guide plate 11. For example, the reflectionsheet 10 defines a resin sheet having a thickness of about 0.1 to 2 mm.In the present embodiment, the front face of the reflection sheet 10 ispainted white so as to effectively reflect the light emitted from theback face 11 c toward the side of the light guide plate 11, so that theuse efficiency of the light can be improved to enhance the luminance ofthe light on the light exit face lib of the light guide plate 11.

Thus, including the optical sheets 7 to 9, the light guide plate 11 andthe reflection sheet 10, the illuminating device 4 is capable of makingthe light emitted from the LEDs 21 into planar light to project theplanar light onto the back face of the liquid crystal display panel 3. Apower board 18 arranged to supply power to the LED board 20, and acontrol board 19 arranged to drive the liquid crystal display panel 3are provided behind the chassis 4.

The LED board 20 includes a radiating plate 22 made from metal such asaluminum as shown in FIG. 3. The LED board 20 has a rectangular shape.The LED board 20 includes an insulating layer 23 disposed on the frontface of the radiating plate 22. The LEDs 21 (thirteen pieces in thepresent embodiment) are aligned on the insulating layer 23 in alongitudinal direction of the LED board 20 (radiating plate 22). TheLEDs 21 are connected in series to each other by wiring patternsprovided on the insulating layer 12 (not illustrated).

In the present embodiment, the radiating plate 22 has the function of abase member, and is arranged to prevent a rise in temperature by heatgenerated from the LEDs 21. In the present embodiment, the radiatingplate 22 is attached to be fixed to the plate 15 a of the light sourceholding member 15 by a thermal conductive sheet that has adhesive faceson both sides (not illustrated). Thus, the heat generated from the LEDs21 is conducted to the bottom plate 14 a of the chassis 14 via theradiating plate 22, the thermal conductive sheet and the light sourceholding member 15, which can prevent an excessive rise in temperature ofthe LEDs 21.

Each of the LEDs 21 has a package structure such that an LED chip thatemits blue light is encapsulated in a transparent resin into which ayellow fluorescent material is mixed, for example. Thus, the LEDs 21 arecapable of emitting white light from the light emitting surfaces 21 a.

The plate 15 b of the light source holding member 15 is disposed suchthat an end portion 15 d thereof is disposed so as to overlap with theback face of the end portion 11 d of the light guide plate 11 when seenin a plan view as shown in FIG. 3. In this case, the fixation screws 16are disposed at a portion between the end portion 15 d of the plate 15 band the back face of the end portion 11 d of the light guide plate 11where the end portion 15 d and the back face of the end portion 11 doverlap each other. Thus, the fixation screws 16 are disposed such thatscrew heads 16 a thereof jut toward the back face of the end portion 11d of the light guide plate 11.

In the present embodiment, the light guide plate 11 includes concaveportions 12, which are dented to the front side of the light guide plate11, on the back face of the end portion 11 d of the light guide plate 11at positions where the screw heads 16 a of the fixation screws 16 are tobe disposed. The concave portions 12 each have openings that are largerthan the external diameter of the screw heads 16 a of the fixationscrews 16. The concave portions 12 have a depth larger than the heightof the screw heads 16 a of the fixation screws 16. Thus, getting intothe concave portions 12, the screw heads 16 a of the fixation screws 16can be prevented from making contact (interference) with the innersurfaces of the concave potions 12.

As described above, the configuration of including the concave portions12 disposed at the given positions on the back face of the end portion11 d of the light guide plate 11 can prevent contact (interference)between the light guide plate 11 and the screw heads 16 a of thefixation screws 16 disposed on the back face side of the end portion 11d, which can accordingly prevent shavings 118 from being produced fromthe light guide plate 11 when the light guide plate 11 is shaken asshown in FIG. 18B.

Thus, because no shavings 118 are produced, the illuminating device 4 isfree from a problem that shavings 118 adhere to the light emittingsurfaces 21 a of the LEDs 21 or enter into the front face side of theoptical sheets 7 to 9 to make luminance unevenness develop in imagesdisplayed on the liquid crystal display device 1 to reduce the displayquality.

The concave portions 12 of a first embodiment define concave portions12A having round openings as shown in FIGS. 4A and 4B, which aredisposed at the given positions on the back face of the end portion 11 dof the light guide plate 11. Alternatively, the concave portions 12 of asecond embodiment define a concave portion 12B having a strip-shapedopening disposed in a longitudinal direction of the light entrance face11 a of the light guide plate 11, to be specific, an oval opening thatis capable of housing the three screw heads 16 a in a lump, as shown inFIGS. 5A and 5B, which is disposed at a given position on the back faceof the end portion 11 d of the light guide plate 11. In particular,having the configuration shown in FIGS. 5A and 5B of having thestrip-shaped opening when seen in a plan view that is capable of housingthe plurality of screw heads 16 a in a lump, the concave portion 12B canbe produced by making one-time cutting in the back face of the endportion 11 d of the light guide plate 11. Thus, the cost of processingand production of the concave portion 12B can be reduced.

Modifications of the concave portions 12A of the first embodimentdescribed above include concave portions 12C of modification 1 that haveoval openings shown in FIG. 6A, and concave portions 12D of modification2 that have triangular openings shown in FIG. 6B. In addition,modifications of the concave portions 12A of the first embodimentdescribed above include concave portions 12E of modification 3 that havequadrangular openings shown in FIG. 7A, and concave portions 12F ofmodification 4 that have hexagonal openings shown in FIG. 7B.

Next, descriptions of the other preferred embodiment of the presentinvention will be provided with reference to FIGS. 8 to 10B. FIG. 8 isan enlarged cross-sectional view showing relevant components of a liquidcrystal display device of the present embodiment. Explanations of thesame components as those in the above-described embodiment are omitted,and different respects are explained mainly, providing the samereference numerals to the same components as those in theabove-described embodiment.

As shown in FIG. 8, the light guide plate 11 includes concave portions13, which are dented to the front side of the light guide plate 11, onthe back face of the end portion 11 d of the light guide plate 11 atpositions where the screw heads 16 a of the fixation screws 16 are to bedisposed, and the concave portions 13 each have openings having a notchshape extending from the light entrance face 11 a. The openings of theconcave portions 113 are larger than the external diameter of the screwheads 16 a of the fixation screws 16. The concave portions 13 have adepth larger than the height of the screw heads 16 a of the fixationscrews 16. Thus, getting into the concave portions 13, the screw heads16 a of the fixation screws 16 can be prevented from making contact(interference) with the inner surfaces of the concave potions 13.

As described above, the configuration of including the concave portions13 disposed at the given positions on the back face of the end portion11 d of the light guide plate 11 can prevent contact (interference)between the light guide plate 11 and the screw heads 16 a of thefixation screws 16 disposed on the back face side of the end portion 11d of the light guide plate 11, which can accordingly prevent shavings118 from being produced from the light guide plate 11 when the lightguide plate 11 is shaken as shown in FIG. 18B.

The concave portions 13 of a third embodiment define concave portions13A having quadrangular openings as shown in FIGS. 9A and 9B, which aredisposed at the given positions on the back face of the end portion 11 dof the light guide plate 11 so as to have a notch shape extending fromthe light entrance face 11 a. Alternatively, the concave portions 13 ofa fourth embodiment define a concave portion 13B having a strip-shapedopening disposed in the longitudinal direction of the light entranceface 11 a of the light guide plate 11, to be specific, an rectangularopening that is capable of housing the three screw heads 16 a in a lump,as shown in FIGS. 10A and 10B, and the concave portion 13B is disposedat a given position on the back face of the end portion 11 d of thelight guide plate 11 so as to have a notch shape extending from thelight entrance face 11 a. In particular, having the configuration shownin FIGS. 10A and 10B of having the strip-shaped opening when seen in aplan view that is capable of housing the plurality of screw heads 16 ain a lump, the concave portion 13B can be produced by making one-timecutting in the back face of the end portion 11 d of the light guideplate 11. Thus, the cost of processing and production of the concaveportion 13B can be reduced.

Modifications of the concave portions 13A of the third embodimentdescribed above include concave portions 13C of modification 1 that haveround openings shown in FIG. 11A, and concave portions 13D ofmodification 2 that have oval openings shown in FIG. 11B. In addition,modifications of the concave portions 13A of the third embodimentdescribed above include concave portions 13E of modification 3 that havetriangular openings shown in FIG. 12A, and concave portions 13F ofmodification 4 that have hexagonal openings shown in FIG. 12B.

Used in the above embodiments is the light source holding member 15having has the L-shape; however, it is also preferable to use the lightsource holding member 15 consisting of the plate 15 a and the plate 15b, which are disposed so as to have an inverted T-shape as shown in FIG.13A, as modification 1. Alternatively, it is also preferable to use thelight source holding member 15 consisting of the plate 15 a and theplate 15 b, which are disposed so as to have a laterally laid U-shape asshown in FIG. 13B, as modification 2. Alternatively, it is alsopreferable to use the light source holding member 15 consisting of theplate 15 a and the plate 15 b, which are disposed so as to have aninverted Y-shape as shown in FIG. 14, as modification 3.

Used in the above embodiments as the fixation members arranged to fixthe light source holding member 15 to the bottom plate 14 a of thechassis 14 are the fixation screws 16 such as flat head screws or thehexagonal screws; however, it is also preferable to use rivets 31 shownin FIG. 15A as modification 1. Alternatively, it is also preferable touse clips 32 arranged to sandwich the plate 15 b of the light sourceholding member 15 and the bottom plate 14 a of the chassis 14 shown inFIG. 15B as modification 2.

The foregoing description of the preferred embodiments of the presentinvention has been presented for purposes of illustration anddescription with reference to the drawings. However, it is not intendedto limit the present invention to the embodiments, and modifications andvariations are possible as long as they do not deviate from theprinciples of the present invention. For example, described in theabove-described embodiments is the configuration that an LED board isdisposed opposed to one long side of a rectangular-shaped light guideplate; however, the number of LED boards to be included is changeableappropriately. For example, it is preferable that LED boards aredisposed opposed to a pair of opposed long sides of the light guideplate. Alternatively, it is preferable that LED boards are disposedopposed to one long side and one short side of the light guide plate.Alternatively, it is preferable that LED boards are disposed opposed tothe four sides of the light guide plate. In this case, the concaveportions 12A to 12F, 13A to 13F can be chosen appropriately to bedisposed on the back faces of the end portions on the sides of the lightguide plate, where the LED boards are disposed opposed to the sides.

1. An illuminating device comprising: a light guide plate that isdisposed on an inner bottom face of a chassis, the light guide platecomprising: a light entrance face disposed on a lateral end face of thelight guide plate, from which light projected from a light sourceenters; and a light exit face having a planar shape disposed on an upperface of the light guide plate, from which the entering light exits; anda light source holding member that is disposed on an inside face of thechassis while opposed to the light entrance face of the light guideplate, and comprises the light source arranged to project the light ontothe light entrance face of the light guide plate, wherein the lightsource holding member is fixed to the inner bottom face of the chassisby a fixation member, and wherein the illuminating device furthercomprises a concave portion on a back face of the light guide plate, theconcave portion being arranged to prevent contact with a jutting end ofthe fixation member.
 2. The illuminating device according to claim 1,wherein the light source holding member further comprises: a plate towhich the light source is attached; and a plate arranged to be fixed toa bottom plate of the chassis by the fixation member, the plates beingdisposed having an L-shape, wherein an end portion of the plate arrangedto be fixed to the bottom plate of the chassis, the end portion beingdisposed on a side of the light guide plate, overlaps with a back faceof an end portion of the light guide plate when seen in a plan view. 3.The illuminating device according to claim 1, wherein the light sourceholding member further comprises: a plate to which the light source isattached; and a plate arranged to be fixed to a bottom plate of thechassis by the fixation member, the plates being disposed having aninverted T-shape, wherein an end portion of the plate arranged to befixed to the bottom plate of the chassis, the end portion being disposedon a side of the light guide plate, overlaps with a back face of an endportion of the light guide plate when seen in a plan view.
 4. Theilluminating device according to claim 1, wherein the light sourceholding member further comprises: a plate to which the light source isattached; and a plate arranged to be fixed to a bottom plate of thechassis by the fixation member, the plates being disposed having alaterally laid U-shape, wherein an end portion of the plate arranged tobe fixed to the bottom plate of the chassis, the end portion beingdisposed on a side of the light guide plate, overlaps with a back faceof an end portion of the light guide plate when seen in a plan view. 5.The illuminating device according to claim 1, wherein the light sourceholding member further comprises: a plate to which the light source isattached; and a plate arranged to be fixed to a bottom plate of thechassis by the fixation member, the plates being disposed having aninverted Y-shape, wherein an end portion of the plate arranged to befixed to the bottom plate of the chassis, the end portion being disposedon a side of the light guide plate, overlaps with a back face of an endportion of the light guide plate when seen in a plan view.
 6. Theilluminating device according to claim 1, wherein the concave portionhas a notch shape extending from the light entrance face of the lightguide plate.
 7. The illuminating device according to claim 1, whereinthe fixation member comprises a plurality of fixation members that aredisposed in a longitudinal direction of the light entrance face of thelight guide plate, and wherein the concave portion has a strip shapewhen seen in a plan view to house the plurality of fixation members in alump.
 8. The illuminating device according to claim 1, wherein theconcave portion has a round shape when seen in a plan view.
 9. Theilluminating device according to claim 1, wherein the concave portionhas an oval shape when seen in a plan view.
 10. The illuminating deviceaccording to claim 1, wherein the concave portion has a triangular shapewhen seen in a plan view.
 11. The illuminating device according to claim1, wherein the concave portion has a quadrangular shape when seen in aplan view.
 12. The illuminating device according to claim 1, wherein theconcave portion has a hexagonal shape when seen in a plan view.
 13. Theilluminating device according to claim 1, wherein the fixation membercomprises a flat head screw.
 14. The illuminating device according toclaim 1, wherein the fixation member comprises a hexagonal screw. 15.The illuminating device according to claim 1, wherein the fixationmember comprises a rivet.
 16. The illuminating device according to claim1, wherein the fixation member comprises a clip arranged to sandwich thelight source holding member and the bottom plate of the chassis.
 17. Adisplay device comprising: the illuminating device according to claim 1;and a display panel arranged to make a display by using the lightemitted from the illuminating device.
 18. The display device accordingto claim 17, wherein the display panel comprises a liquid crystaldisplay panel comprising a pair of substrates, and liquid crystalsfilled between the substrates.
 19. A television receiving device thatcomprises the display device according to claim 17.